Archive for the ‘Materials’ Category

Phosphorescent organic light-emitting diodes (PhOLEDs) offer high quantum efficiency compared to conventional fluorescent OLEDs because they can harness both singlet and triplet exitons for emission. Green and red PhOLEDs with 100% internal quantum efficiency have been reported, but highly efficient and stable blue PhOLEDs have yet to be developed because of the lack of suitable host materials possessing higher triplet energy levels than blue phosphors. In this hot paper Chuluo Yang, Dongge Ma and colleagues report two simple CBP isomers with high triplet energies as efficient hosts for blue phosphorescent OLEDs, and the efficiencies of the o-CBP-based device are over 2 times higher than those of CBP. Interested to know more? Read the article for free until 2nd March. (Free registration required)

Scientists in China have come up with a green way to reduce graphene oxide so that it can be used in the biomedical field.

The team has used the anticoagulant heparin, a straight-chain anionic glycosaminoglycan and a natural polymer, to reduce and stabilise the graphene oxide. The heparin–reduced graphene oxide sheets show excellent biocompatibility and activity as a blood anticoagulant, according to the researchers. They also say that the heparin–reduced graphene oxide could bind strongly to anticancer drugs for highly efficient loading.

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Stacking-induced phosphorescence from organic radical materials. A new class of organic phosphorescent materials have been developed by scientists at University of Science and Technology of China. Based on salts of an organic radical material, the phosphorescent complexes show stacking-induced white-light and blue-light phosphorescence. The team say that these materials could lead to new LEDs.

Hydrolysis of polysaccharides in unused biomass offers a sustainable method to produce glucose and other chemicals derived from it.

In an effort to make the process more commercially viable, scientists at Qingdao Institute of Bioenergy and Bioprocess Technology, China, have designed and synthesized efficient catalysts for the hydrolysis of starch and cellulose based on copolymers of poly(acrylic acid) and poly(styrene sulfonic acid). The random copolymer PAA-r-PSSH gave the highest glucose yield among the prepared catalysts which the team attribute to the synergic effect of the SO3H and COOH groups in the polymer chain.

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Au@Pd bimetallic nanoparticles were successfully dispersed on graphene by a simple one step reducing method.

The bimetallic nanoparticles show superior catalytic activity over the monometallic counterparts. Including the Au core minimizes the use of more expensive Pd precursors and plays an important role in enhancing the catalytic activity arising from the strong catalytic bimetallic electronic ligand interactions. The composition and shell thickness of the nanoparticles is controlled by loading different amounts of the metallic precursors. Interested to know more? Read the article for free until 16th December…

A chameleon cloth that changes colour in response a drop in oxygen concentration could be used to warn of oxygen deficient areas say Chinese scientists.

The colour of the cloth gradually changes from red to purple to blue as the oxygen concentration increases. The light, soft and flexible cotton cloth could be easily included in clothes to make wearable sensors the team say.

A soft porous crystal which changes its fluorescence in response to mechanical grinding and heat has been developed by scientists in China.

Applying mechanical force changes the organic crystal’s fluorescence from yellow through to cherry red. Heating the crystal reverses this. The team say this mechanofluorochromism is caused by the crystal going through multiple structural transformations.